The present disclosure relates to a gas sensor and a gas detection method.
Hydrogen is widely used in chemical products such as fuel cells, synthetic resins, and pharmaceutical products. Hydrogen gas has a low molecular weight and therefore has a tendency to leak, and additionally has a wide explosive concentration range, and thus, techniques to measure the concentration of hydrogen gas are important. Hydrogen has a low molecular weight and the speed of sound in hydrogen gas is faster than in other gases, and thus, there are techniques for measuring the concentration of hydrogen gas by detecting changes in the speed of sound.
Non-Patent Document 1 (IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, VOL. 50, No. 9, SEPTEMBER 2003) discloses a technique in which the hydrogen gas concentration is measured by causing a gas inside a container provided with an opening to undergo Helmholtz resonance by being oscillated by one piezoelectric element disposed in the container, and calculating the speed of sound from the resonant frequency thereof.